Sorry but that feature is no longer available.
Calvin and Hobbes by Bill Watterson for September 15, 1990
Transcript:
Dad: Ok Calvin, let's check over your math homework. Calvin: Let's not and say we did. Dad: Your teacher says you need to spend more time on it. Have a seat. Calvin: More time?! I already spent ten whole minutes on it! Ten minutes shot! Wasted! Down the drain! Dad: You've written here 8 + 4 = 7. Now you know that's not right. Calvin: So I was off a little bit. Sue me. Dad: You can't add things and come out with less than you started with! Calvin: I can do that! It's a free country! I've got my rights!
Not unless you add negative numbers. But that’s still subtraction.